Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and closed-world scope, so the safety profile is covered; the description redundantly restates 'Read-only' but usefully adds the concrete return shape {id, title, text, url} and what the payload contains per record type. That is real added context beyond the structured fields, though error/not-found behavior is still unspecified.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loaded with the verb and the core mechanic, then a compact per-type breakdown, then the return shape and the 'not a web fetch' caveat. It is dense but well organized; the id-format patterns are repeated nearly verbatim from the parameter schema, which is the only real redundancy.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a one-parameter lookup with no output schema, the description supplies what the structured data does not: the per-id-type payload contents and the exact return envelope {id, title, text, url}. Combined with annotations covering safety and a 100%-documented schema, an agent has everything needed to call it correctly.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100% and the single id parameter is fully documented in the schema with the same three format patterns. The description reinforces the format but adds no syntax or validation detail beyond what the schema already gives, so the baseline 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb (fetches) and enumerates exactly what resource kinds can be retrieved (brand, campaign, help answer), each with its id shape and the fields it carries. It also explicitly disambiguates from a sibling concept ('Not a web fetch — ids come from search'), so an agent can distinguish it from 'search' and from the typed getters like get_brand_guide without opening a schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

It clearly states the precondition for use — the id must come from a prior search — and rules out the most likely misreading (web fetch). What is missing is explicit routing versus siblings that also return brand/campaign data (get_brand_brief, list_brands), i.e. when to fetch by id rather than call a typed getter.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.